Pin post-status-check action in test.yml to full commit SHA

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nogates

.github/workflows/test.yml

@@ -71,7 +71,7 @@ jobs:
           scope: DataDog/datadog-api-spec
           policy: datadog-api-client-python.github.post-status-check.pull-request
       - name: Post status check
-        uses: DataDog/github-actions/post-status-check@v2
+        uses: DataDog/github-actions/post-status-check@65b4875f33ad773d7ba4b005a2cb5f35020295f3 # v2.3.0
         with:
           github-token: ${{ steps.octo-sts.outputs.token }}
           repo: datadog-api-spec